NOS tires

[SuperCars]

What year or time frame did the "DOT" appear on regular production tires. The reason I ask is that I've seen early 70's vintage Goodyear tires with "DOT" on them which were not produced by the Reproduction Tire companies of today.

I've also seen a set of vintage Uniroyal Loredo tires of the correct size and exact kind which were used by GM for 67 vettes, and these had "DOT" on them. These were definitely NOS as Uniroyal quit making those many, many years ago, and no Company is reproducing them today.

With this question and realizing that there were NOS tires produced in the early 70's with "DOT" on them, do we still consider those NOS? If yes, the old rule of thumb of asking do they have "DOT" on them would not apply.